The proposed project is a continuation of research on the effects of marihuana (delta-9-tetrahydrocannabinol) on the reproductive system. Sexually mature female Rhesus monkeys are administered tetrahydroxannabinol (THC) and gonadotrophic hormones and sex steroids are measured. The initial phase of this study has shown that THC can alter reproductive hormones in both male and female monkeys. The proposed continuation of this research will further define the effects of THC and other cannabis derivatives on the hormonal control of the menstrual cycle and on fertility in the female monkey. The study will provide information on the mechanisms by which THC alters reproductive hormones and the blood levels of THC necessary to produce these effects.